Method for ceramic electroplating a cylinder assembly of an internal combustion engine

ABSTRACT

A method for ceramic electroplating a cylinder assembly of an internal combustion engine is provided, wherein an engine cylinder assembly&#39;s aluminum alloy based work-pieces having been inspected are chemically degreased and roughened, placed into an electroplating tank containing an electroplating solution and an additive, with blowing air for stirring the electroplating solution. After the work-pieces in the electroplating tank are suspended on cathode hook-bars, nickel plates are disposed in the anode and the right middle of the cylinder inner-wall is connected to a current auxiliary anode with a voltage, metallic ions and ceramic materials in the electroplating solution accumulate on the work-pieces and a electroplating layer is formed alternatively stacked with one metal alloy layer by one ceramic layer. The ceramic is electroplated on the surface of the aluminum alloy based work-pieces. After the work-pieces are taken out, cleaned and grinding, the parts having smooth and lubricative surfaces are gained.

FIELD OF THE INVENTION

The present invention relates to a method for ceramic electroplating acylinder assembly of an internal combustion engine, and particularly toa method for electroplating ceramic material on the outer wall of apiston and on the surface of a cylinder inner-wall, which causes theengine cylinder assembly not only has a smooth and lubricative surfacelayer, resistance to oxidation at high temperature and increased kineticenergy (horse power), but also has more conformation with environmentalprotection, prolonged service life of cylinder and heat resistance (heatdissipation).

BACKGROUND OF THE INVENTION

In general, in order to solve a problem that has difficulty to providecylinder inner-wall with a lubrication effect which can provide a pistonfor extended reciprocal movement as well as reduced friction coefficientand increased kinetics power by adding lubricant into fuel in acylinder, those in the art may use a lubricating oil which causes theouter wall of a piston very close to the surface of a cylinderinner-wall when the piston reciprocally travel in the cylinderinner-wall, which has little lubricating effect for the reciprocaltravel of the piston and also can not eliminate the increased thefriction between the piston and the cylinder inner-wall during thereciprocal travel which causes decreased kinetic energy (horse power).

It is well-known that ceramic material can provide the outer wall of apiston reciprocally traveling along the cylinder inner-wall for a longtime with excellent properties such as well-lubricating effect,resistance to oxidation at high temperature, high hardness, heatresistance and long-wearing, and mean while, the ceramic material can beelectroplated on the surface of a work-piece to have a thickness thereofon the work-piece according to the requirement, which cause thework-piece also has smooth and lubricative surface with the ceramicproperties such as resistance to oxidation at high temperature, highhardness, heat resistance and long-wearing; however, conventionalelectroplating methods are not suitable for surface treatment of analuminum alloy based cylinder assembly of an internal combustion engine,since the reciprocating movement of the piston of a cylinder assembly ofan internal combustion engine along the cylinder inner-wall has furtherlubricating effect; besides, for an automobile, an airplane and avessel, etc., the intake, ignition, explosion and exhaust of the enginecylinder typically are functioned over the top of the piston to make thepiston moving in the cylinder body for generating expansion andcompression stroke reciprocally, so the lubricant between the piston andthe cylinder inner-wall do not have appropriate reciprocal movementwhich causes the limited reciprocal movement of the cylinder assembly ofan internal combustion engine without damage, but this also constraintthe application of ceramic material in the electroplating process of acylinder assembly of an internal combustion engine, because, since thehard nature and fragility of ceramic material, if ceramic material iselectroplated on the engine cylinder assembly, the ceramic layer is aptto fall off because it cannot sustain the lubrication action generatedby the unavoidable reciprocal movement of the engine cylinder assembly.Thus, this problem becomes an unbreakable technical bottleneck of theceramic electroplating method for application of the surface treatmentof a cylinder assembly of an internal combustion engine which requiresreciprocating motion.

SUMMARY OF THE INVENTION

Accordingly, the object of the present invention is to provide a methodfor ceramic electroplating a cylinder assembly of an internal combustionengine which requires a reciprocating movement. By this design, acylinder assembly of an internal combustion engine has properties ofceramic material, such as resistance to oxidation at high temperature,heat resistance and long-wearing to have softness with smooth andlubricative features and thus has reduced frictional resistance,accelerated kinetics power and prolonged service life of cylinder forincreasing the kinetic energy (horse power).

To achieve the noted object of the present invention, the technicalmeans utilized by the present invention is to provide a method forceramic electroplating a cylinder assembly of an internal combustionengine, comprising the following steps: after an engine cylinderassembly's aluminum alloy based work-pieces having been inspected arechemically degreased and roughened, placed into a electroplating tank,containing a electroplating solution formulated from Nickel Sulfate,Nickel Chloride and Boric acid and an additive formulated from ceramicpowder, metal alloy powder, Sodium citrate, and adding softening agentinto the electroplating tank, and blowing air by an air tube installedtherein for stirring the electroplating solution, which not only causesthe electroplating solution and the additive become uniform but alsoincreases the electroplating rate; and after the work-pieces in theelectroplating tank are suspended on cathode hook-bars while nickelplates are disposed in the anode and the right middle of the cylinderinner-wall is also connected to a current auxiliary anode with asuitable voltage, thus causes metallic ions and ceramic material in theelectroplating solution accumulate on the work-pieces and forms aelectroplating layer alternatively stacked with one metal alloy layer byone ceramic layer, so that the ceramic is electroplated on the surfaceof the work-pieces, and then after the work-pieces are taken out andcleaned for grinding, thus completing the cylinder assembly of aninternal combustion engine having smooth and lubricative surfaces,resistance to oxidation at high temperature, heat resistance (heatdissipation), long-wearing, gasoline saving, conforming withenvironmental protection and softness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart according to an embodiment of the presentinvention;

FIG. 2 shows a 3-D appearance diagram of a piston according to anembodiment of the present invention;

FIG. 3 shows an assembling illustrative diagram of a cylinder assemblyof an internal combustion engine according to an embodiment of thepresent invention;

FIG. 4 shows an upward-viewing illustrative diagram of an auxiliaryanode of a cylinder inner wall of an internal combustion engineaccording to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, referring to FIG. 1, the steps for performing the presentinvention are:

-   a. Inspection 1: inspecting engine cylinders of internal combustion    engines if the surface or appearance of aluminum alloy based    work-pieces thereof have any defect or flaw, and eliminating the    defects;-   b. Arrangement 2: arranging the inspected work-pieces in order;-   c. Chemically degreasing 3: placing the work-pieces into a    chemically degreasing sink for a degreasing operation, wherein the    chemically degreasing sink contains a weak alkaline solution with    concentration 10-20%, and the time of the degreasing operation is    about 5-30 minutes to allow the grease becoming soluble compounds    for removing;-   d. Cleaning 4: placing the chemically degreased work-pieces into a    tank for cleaning by purified water;-   e. Suspension 5: suspending the cleaned work-pieces;-   f. Roughening 6: transporting the suspended work-pieces into a    sodium hydroxide (NaOH) solution tank for roughening to make the    surfaces thereof have capillarity;-   g. Cleaning 7: placing the roughened work-pieces into a bath    containing purified water for cleaning;-   h. Activation 8: placing the cleaned work-pieces into a solution    tank added with nitric acid HNO₃ for removing aluminum oxide on the    surfaces of the work-pieces and activating the surfaces at the same    time;-   i. Cleaning 9: placing the activated work-pieces a bath containing    purified water for cleaning;-   j. Zincating 10: using a chemical agent to form a film on the    surface of the work-pieces for treating as a bridge for ceramic    electroplating process;-   k. Cleaning 11: placing the zincated work-pieces into a bath    containing purified water for cleaning;-   l. Ceramic electroplating 12: placing the zincated work-pieces into    a electroplating tank and acting as a cathode as shown in FIG. 4,    and hanging a nickel plate as anode in the electroplating tank, in    which the electroplating solution formulated from Nickel Sulfate,    Nickel Chloride and Boric acid, and an additive formulated from    ceramic powder, metal alloy powder, Sodium citrate and softening    agent, are added into the electroplating tank, wherein the metal    alloy powder can selected based on the hardness, hue and the likes    according with the requirements of the finished product, and the    softening agent can be 2-ethyl hexyl Sulfate and wherein 1 liter of    the electroplating solution and additive is formulated from 150    g-300 g Nickel Sulfate, 25 g-60 g Nickel Chloride, 15 g-45 g Boric    acid, along with 50 g-200 g ceramic powder, 5 g-50 g Sodium citrate    and 5 g-30 g other metal alloy powder, with PH between 3.5 and 5;    and the working temperature of the electroplating tank is in the    range of 50° C.-70° C., an air tube blows air into the    electroplating tank for stirring the electroplating solution and the    additive sufficiently, and after the electroplating tank applies a    3V-7V voltage and a 50A-500A current, which the amount of the    current is determined by the number of the work-pieces, which causes    metallic ions and ceramic material in the electroplating solution to    accumulate on the work-pieces and forms a electroplating layer    alternatively stacked with metal alloy layers and ceramic layers,    thus electroplating ceramic on the surface of the work-pieces to    form ceramic parts having required thickness according with the    ceramic material of a piston 30 and a inner wall 21 of a cylinder 20    of a cylinder assembly of an internal combustion engine; and then    connecting a right middle 210 of the inner wall 21 of the cylinder    20 to a current auxiliary anode which causes ceramic electroplating    layer at the right middle 210 become uniform and has better electric    conducting adhesion as shown in FIG. 4;-   m. Cleaning 13: transporting the parts electroplated with ceramic    into a bath for cleaning with running purified water;-   n. Blow-drying 14: after the cleaned parts blow-dried, taking off    from suspension hooks;-   o. Grinding 15: surface treating the blow-dried ceramic parts via    grinding (such as, polishing) which makes the ceramic parts having    smooth and lubricative surfaces, whereby completing finished    products 16.

By the implementation flow of the above-mentioned method, the presentinvention can be applied to a reciprocal-moving cylinder assembly of aninternal combustion engine. Since ceramic material has excellentproperties such as high hardness, heat resistance, long-wearing, highlubrication and resistance to oxidation at high temperature. Therefore,the present invention electroplates ceramic material on the holes of theinner wall 21 and the outer wall surface 31 of a cylinder of an internalcombustion engine as shown in FIGS. 2 and 3, which can cause the innerwall 21 of the cylinder 20 and the outer surface 31 of the piston 30 ofan internal combustion engine have the properties of the ceramicmaterial such as well-lubricating effect, heat resistance, long-wearingand resistance to oxidation at high temperature. After the presentinvention applies to a cylinder assembly of an internal combustionengine used by an automobile, an airplane and a vessel, etc., the smoothsurface of the piston 30 and the inner wall 21 of the cylinder 20 hashigh lubrication in compression stroke, reduced friction coefficient andincreased power efficiency; furthermore, since the surface has a ceramicelectroplated cylinder assembly of an internal combustion engine, notonly can reach the object of gasoline saving but also conforming withenvironmental protection due to no smoke emission and prolonged servicelife.

1. A method for ceramic electroplating a cylinder assembly of aninternal combustion engine comprising: inspecting engine cylinders of aninternal combustion engine if the surface or appearance of aluminumalloy based work-pieces thereof have any defect or flaw, and eliminatingthe defects; arranging the inspected work-pieces in order; placing thework-pieces into a chemically degreasing sink for a degreasingoperation, wherein the chemically degreasing sink contains a weakalkaline solution with concentration 10-20%, and the time of thedegreasing operation is about 5-30 minutes to allow the grease becomingsoluble compounds for removing; placing the chemically degreasedwork-pieces into a tank for cleaning by purified water; and transportingthe cleaned and suspended work-pieces into a sodium hydroxide (NaOH)solution tank for roughening to make the surfaces thereof havecapillarity; and then placing the roughened work-pieces into a bathcontaining purified water for cleaning; placing the cleaned work-piecesinto a solution tank added with nitric acid HNO₃ for removing aluminumoxide on the surfaces of the work-pieces and activating the surfaces atthe same time; placing the activated work-pieces a bath containingpurified water for cleaning; and then zincating in which uses a chemicalagent to form a film on the surface of the work-pieces for treating as abridge for ceramic electroplating process; placing the zincatedwork-pieces into a bath containing purified water for cleaning; andplacing the zincated work-pieces into a electroplating tank and actingas a cathode and hanging a nickel plate as anode in the electroplatingtank, meanwhile, in which the electroplating solution formulated fromNickel Sulfate, Nickel Chloride and Boric acid, and an additiveformulated from ceramic powder, metal alloy powder, Sodium citrate andsoftening agent, are added into the electroplating tank, wherein themetal alloy powder can selected based on the hardness, the hue and thelikes according with the requirements of the finished product, and thesoftening agent can be 2-ethyl hexyl Sulfate; and 1 liter of theelectroplating solution and additive is formulated from 150 g-300 gNickel Sulfate, 25 g-60 g Nickel Chloride, 15 g-45 g Boric acid, alongwith 50 g-200 g ceramic powder, 5 g-50 g Sodium citrate and 5 g-30 gother metal alloy powder, with PH between 3.5 and 5; and the workingtemperature of the electroplating tank is in the range of 50° C.-70° C.,an air tube blows air into the electroplating tank for stirring theelectroplating solution and the additive sufficiently, and after theelectroplating tank applies a 3V-7V voltage and a 50A-500A current,which the amount of the current is determined by the number of thework-pieces, which causes metallic ions and ceramic material in theelectroplating solution to accumulate on the work-pieces and forms aelectroplating layer alternatively stacked with metal alloy layers andceramic layers, thus electroplating ceramic on the surface of thework-pieces to form ceramic parts having required thickness accordingwith the ceramic material of a piston and a inner wall of a cylinder ofa cylinder assembly of an internal combustion engine; and thenconnecting a right middle of the inner wall of the cylinder to a currentauxiliary anode which causes ceramic electroplating layer at the rightmiddle become uniform; transporting the parts electroplated with ceramicinto a bath for cleaning with running purified water; after the cleanedparts blow-dried, taking off from suspension hooks; surface treating theblow-dried ceramic parts via grinding (such as, polishing) which makesthe ceramic parts having smooth and lubricative surfaces, wherebycompleting finished products.